: Latest development build

Add test coverage for StashID count filter

Adds comprehensive test coverage for the stash_id_count scene filter
introduced in commit 19134c892e941be67eba8aea7e99b0b75f76a61c.

The test validates all comparison modifiers (equals, not equals, greater
than, less than) across multiple count values (0, 1, 2) to ensure the
filter works correctly for scenes with varying numbers of Stash IDs.

Changes:
- Add TestSceneQueryStashIDCount test function
- Add verifyScenesStashIDCount helper function
- Create test fixtures for scenes with 0 and 2 StashIDs
- Test all IntCriterionInput modifiers with boundary values

The test follows the established pattern used by other count filter tests
(tag_count, performer_count) and ensures the SQL join and count logic
work correctly for all edge cases including scenes with no StashIDs.